Water for La Marzocco Linea Micra

#1: Post by **comet082** » May 28th, 2023, 10:23 pm

Hi all,

I recently upgraded my machine to Linea Micra from La Marzocco and I'm trying to make sure I have good water for the machine. I would like to avoid using bottled water if possible.. However, I'm open to it if that's my only option.

I tested my home tap water using the la marzocco test kit, pH/TDS meter test kit, and GH/KH test kit. From the results, it looks like the alkalinity, hardness, and TDS are a bit low and the chloride level (although less than 30) is not close to 0. I'm concerned about possible corrosion/scaling.

Here are the tap water results:
* Alkalinity = 2 KH (2 drops) = 35.8 ppm
* Hardness = 3 GH (3 drops) = 53.7 ppm
* Free chlorine = 0.4 ppm
* Total chlorine = between 0.05-0.1 ppm
* PH = 7.3 (measured by TDS/pH meter)
* TDS = 50-52 ppm (measured by TDS/pH meter)
* Iron = 0-0.5 ppm
* Chloride = 24 ppm

I also tested the Brita filtered water with the GH/KH kit and pH/TDS meter just to see and the results don't seem very good. Brita filtered water results:
* Alkalinity = 1 KH = 17.9 ppm
* Hardness = 2 GH = 35.8
* PH = 6.78
* TDS = 36 ppm

So my questions are:
1. Can I use my tap water for the machine without worrying too much about corrosion or scaling?
2. Should I add a little bit of potassium bicarbonate to my tap water to increase the alkalinity to 50 ppm?
3. Would a BWT penguin pitcher be helpful for my tap water situation?
4. If a BWT penguin pitcher is recommended, should I still add potassium bicarbonate?
5. Should I use zero water and add magnesium sulfate & potassium bicarbonate for alkalinity 50 ppm and hardness 80 ppm?

Thanks for any input! I really appreciate it in advance!

#2: Post by **Jeff** » May 28th, 2023, 11:30 pm

Removing the chlorine or chloramine from your water is generally a good idea. I think most people would agree that it improves the taste, or at least doesn't make it worse. Removing those won't help with the chloride, which can be a concern.

Past staying in the non-scaling region, picking anybody's suggestion for water composition is about like someone telling you how much salt and pepper to put on your food. A lot will depend on your coffees, grinder, basket, and preferred flavor profiles. It's really something that you should try out and then decide first if it is worth the hassle, and then what you want to target for your own preferences.

The chloride seems like it is at 80% of La Marzocco's recommendations. From what I understand, RO is one of the few ways you can get chloride out of your water. For me and the amount of water that I use, I purchase bulk RO/DI water at a local market for around $0.50 a gallon and then use some simple concentrates to pick the GH and KH I want. 20 g of concentrate in a 1 Liter batch works out to 20 ppm, so I don't have to do math too early in the morning.

#3: Post by **homeburrero** » May 29th, 2023, 2:36 am

comet082 wrote:1. Can I use my tap water for the machine without worrying too much about corrosion or scaling?

I think your worry here is small. At ~50 ppm hardness and ~35 ppm alkalinity It's nearly non-scaling at steam boiler temps, and it is clearly less scale prone than water that meets the La Marzocco water recommendation. The chloride is an issue - it is barely below the 30 mg/L level where LM recommends going to RO. And there is no clear cutoff point where chloride stops being an issue. Any chloride may be harmful, and at least one manufacturer (Synesso) recommends that it be below 5 - 15 mg/L. But even at ~30 mg/L it's nowhere close to the 150 mg/L levels where La Marzocco first identified chloride as a problem causing boiler failures in Cambridge MA.

comet082 wrote:2. Should I add a little bit of potassium bicarbonate to my tap water to increase the alkalinity to 50 ppm?
3. Would a BWT penguin pitcher be helpful for my tap water situation?
4. If a BWT penguin pitcher is recommended, should I still add potassium bicarbonate?

You do need a charcoal or carbon filter to remove the chlorine, but my recommendation here would be to avoid the standard Brita or the BWT. They both have decarbonizing (WAC) resins that tend to reduce the alkalinity and acidify the water. That's not something you want here given your borderline chloride ion. For a pitcher filter you could use the newer Brita 'longlast' or 'elite' -- it has no ion exchange resins at all. Most refrigerator filters will work well here also. Nothing wrong with adding a little bicarbonate bump with this water, but if you avoid pitcher filters with WAC resins there is less need to do that.

comet082 wrote:5. Should I use zero water and add magnesium sulfate & potassium bicarbonate for alkalinity 50 ppm and hardness 80 ppm?

That would be advisable if you want to be most cautious about machine healthy water that never requires that you descale. You could try just the potassium bicarbonate (rpavlis water) and try some additional magnesium sulfate (maybe 20 - 80 mg/L as CaCO3) only if you think that it improves taste.

P.S.
You can get better precision from your API test kit if you use a 10 ml sample rather than a 5 ml sample. With a 10 ml sample each drop corresponds to 9.8 mg/L CaCO3 equivalent.